tty0X are missing!The third serial port, sio2 (known as COM3 in DOS), is on
/dev/cuaa2 for dial-out devices, and on
/dev/ttyd2 for dial-in devices. What's the difference
between these two classes of devices?
You use ttydX for dial-ins. When opening
/dev/ttydX in blocking mode, a process will wait for the
corresponding cuaaX device to become inactive, and then wait
for the carrier detect line to go active. When you open the
cuaaX device, it makes sure the serial port isn't already in
use by the ttydX device. If the port's available, it
``steals'' it from the ttydX device. Also, the cuaXX
device doesn't care about carrier detect. With this scheme and
an auto-answer modem, you can have remote users log in and you
can still dialout with the same modem and the system will take
care of all the conflicts.
tty0X are missing!